How can you move your MCP tools beyond plain text? How do you add interactive UI components directly inside chat conversations? This week on the show, Den Delimarsky from Anthropic joins us to discuss MCP Apps and interactive UIs in MCP. Den is a member of the MCP Steering Committee and a Core Maintainer focusing on auth and security. He explains how MCP acts as a universal bridge, providing AI models with the real-time context they need. He shares insights on working with MCP Apps and moving beyond simple text to render web-based user interfaces directly in your chat window. Den previously worked on GitHub Spec Kit, and we discuss taking advantage of spec-driven development and how to use “Skills” to remove the toil from your workflow. We also talk briefly about his podcast and his conversations about navigating careers in technology. This episode is sponsored by AgentField. Course Spotlight: Getting Started With Google Gemini CLI Learn how to use Gemini CLI to bring Google’s AI-powered coding assistance into your terminal for faster code analysis, debugging, and fixes. Topics: 00:00:00 – Introduction 00:02:17 – Den’s Background 00:02:53 – The Work Item Podcast 00:06:55 – Career Move to Anthropic 00:10:24 – What is Model Context Protocol (MCP)? 00:11:39 – MCP UI and MCP Apps 00:16:17 – Sponsor: AgentField 00:17:13 – Structuring MCP Tools 00:24:52 – Cloudflared & tunneling 00:29:59 – Reverse engineering with Ghidra MCP 00:35:43 – Connecting MCP tools 00:43:10 – Video Course Spotlight 00:44:23 – Spec-Driven Development & Context Management 00:57:23 – Leveraging Skills for Model Guidance 01:02:51 – What are you excited about in the world of Python? 01:03:42 – What do you want to learn next? 01:07:14 – How can people follow your work online? 01:07:48 – Thanks and goodbye Show Links: The Work Item Podcast Den Delimarsky - Principal Product Engineer, Tinkerer, Nerd, Trail Explorer Hello, Anthropic · Den Delimarsky What is the Model Context Protocol (MCP)? - Model Context Protocol MCP Apps And Interactive UIs In MCP Clients - Den Delimarsky ext-apps: Official repo for spec & SDK of MCP Apps protocol MCP Will Never Be The Same - Render UI With MCP Apps - YouTube playwright-mcp: Playwright MCP server NationalSecurityAgency/ghidra: Software reverse engineering (SRE) framework GhidraMCP: MCP Server for Ghidra Ralph Loop – Claude Plugin - Anthropic Spec Kit - AI-Powered Specification-Driven Development Toolkit Introducing Agent Skills - Claude Welcome to FastMCP 2.0! - FastMCP uv - Astral